
Last Word
Why do some of our organs come in pairs, but we only have one heart?
Regulars
New ÒÁÈ˾þÃ's popular Last Word series gives readers the opportunity to answer each other's questions about everyday science phenomena, from the shape of scones to the evolutionary history of toenails. To answer a question or ask a new one, email lastword@newscientist.com
Issue no. 3439 published 20 May 2023